Since the advent of vehicles, attempts have been made to provide a suspension system for occupants and cargo carried by the vehicle that isolate the loads from the rough roads over which the vehicle travels. Also, and more recently with the advent of high speed vehicles, it is desirable to provide a suspension system which permits the vehicle to corner at relatively high rates while maintaining the vehicle in a essentially level position. It is also desirable during either acceleration or stopping to maintain the vehicle in an essentially level position. In terms of art, it is highly desirable to be able to control, if not avoid entirely, the roll and pitch that occurs as the vehicle maneuvers.
It is not only desirable to provide an active suspension system that functions to negate movements of the vehicle away from the level, but to provide a relatively comfortable system of suspension including damping of vibrations or movements between the suspended and non-suspended portions of the vehicle while providing a soft resilient ride for the passengers and cargo of the vehicle.
Lotus Motor Company has developed for their motorcars an active spring rate control which utilizes a hydraulic system with electrohydraulic servocontrol valves and hydraulic linear actuators that are controlled by a computer system responding to an accelerometer and gyrosensor mounted on the vehicle. Such system is necessarily complex and extremely expensive.
The object of this invention is to provide a practical means of providing an active suspension system that is less complex and expensive than other systems and one that provides an enhanced ride as compared to the damper controlled systems that are currently in production on vehicles.